An optical backplane, which may be a printed circuit board (PCB), is used to optically couple optical, optoelectrical devices or other PCB's by providing an optical path over which optical signals can be transmitted. Usually optical waveguides are used for providing an optical path to transmit these optical signals over the backplane. In a hybrid approach, these waveguides are integrated or embedded in the backplane. Such a backplane is schematically shown in FIG. 1 and will be discussed below. In order to reduce optical loss in the coupling of this waveguide structure and the components or other PCB's, alignment is a key issue in this area.
U.S. Pat. No. 6,236,788 B1 discloses an arrangement for aligning optical components, wherein an arrangement is provided for coupling light into or out of a waveguide, that is positioned on a base plate. The base plate supports a mirror mount. A holding device for holding optical or opto-electronic components, such as a lens or glass fibre connectors, is provided as well. The mirror mount includes first alignment marks and the holding device includes second alignment marks which snap together with the first alignment marks to permit an alignment in a direction (x-direction) that is parallel to the waveguide. The holding device includes third alignment marks and the base plate includes fourth alignment marks which are used for an alignment in a direction (y-direction) that is perpendicular to the waveguide
However, an alignment arrangement as disclosed in the prior art, does not provide an efficient optical coupling between the first optical path in the holding device and the second optical path defined by the waveguide structure, since the reference marks do not ensure proper alignment. The reference marks only result in an independent alignment in the x-direction or the y-direction. Simultaneous alignment in both the x- and y-direction of the x-y plane is not ensured.